In general, an X-ray tube device including a magnetic field generator is known. Such an X-ray tube device is disclosed in U.S. Pat. No. 6,084,942, for example.
An X-ray tube device disclosed in the aforementioned U.S. Pat. No. 6,084,942 includes a tubular envelope, a cathode and an anode housed in the envelope, and a magnetic field generator arranged outside the tubular envelope. The cathode is provided with an electron source generating a thermoelectron, for example, and a filament current flows thereinto to generate an electron. Furthermore, a negative high voltage is applied to the cathode and a positive high voltage is applied to the anode and the envelope, whereby an electron beam is emitted from the cathode to the anode. The magnetic field generator has a rectangular sectional shape, and a deflecting voltage is applied thereto to generate a magnetic field from the outside of the envelope at a position between the cathode and the anode. Thus, the electron beam to the anode is deflected and is focused to the edge of the anode rotating together with the envelope. The electron beam impinges on the anode to generate an X-ray.